Planned con-rod mod to add additional piston cooling (adding oil squirters).
This is tried & tested in other boxer engines, namely VW (air cooled) & Porsche flat 6 turbos.
An additional groove is machined in each side of the bigend journal to direct the oil, once it has done it's job at the bigend bearing, to the underside of the piston crowns. Where it will assist with pulling heat from the ring lands & piston crown.
Modded Porsche rod:
A ball end mill would be used so the groove will be --U-- shaped not a 'V' as in the above pics ( A 'V' could create a stress riser).
This is how it's done